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    <script>
        // ES6 允许给函数形参赋初始值
        // 1.形参初始值 具有默认值的参数，一般位置要靠后(潜规则)
         function add(a,b, c=10){
            return a+b+c;
         }

         let result = add(1,2)
         console.log(result);

        //  2.与解构赋值结合
        function connect ({host='1270.0.01',username,password,port}){
            console.log(host)
            console.log(username)
            console.log(password)

        }

        connect({            
            host:'hhh',
            username:'root',
            password:'root',
            port:3306}

        );
    </script>
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